Header Right

Genes and Belly Fat

If you store the extra fat in your buttocks and thighs, you are at low risk for being harmed by that extra fat. However, if you store the extra fat primarily in your belly, you are at high risk for becoming diabetic and dying prematurely. People with tiny buttocks and a huge belly probably already have high blood sugar levels that are caused by inability to store their extra fat in their buttocks and thighs. Having a lot of fat stored in your belly almost always means that you have too much fat stored in your liver.

Everybody’s blood sugar rises after meals.

When blood sugar levels rise, the pancreas releases large amounts of insulin to lower blood sugar by driving sugar into the liver.

However, if you have too much fat in your liver, the liver refuses to accept sugar from the bloodstream and blood sugar rises to high levels.

Most cases of diabetes are caused by having too much fat in the liver, so the liver cannot respond to insulin. This is called insulin resistance.

The Danger of Skinny Buttocks and Thighs

A marvelous study from the University of Cambridge in England shows why not being able to store most of your fat in your buttocks and thighs is associated with diabetes (Nature Genetics, November 14, 2016). An international team studied more than two million genetic variants in 200,000 people and found 53 regions of genes associated with insulin resistance, diabetes and heart attacks. They then did CT scan X rays of 12,000 people to see where they stored fat and found that people who are genetically susceptible for diabetes lack the ability to store much fat in their thighs and buttocks.

This means that if you genetically lack the ability to store much fat in the lower part of your body, you are at high risk for becoming diabetic if you gain any excess weight at all. We have known for many years that having skinny thighs and buttocks is a major independent risk factor for diabetes, even if you are not obese. For example, a low thigh circumference was shown to be associated with increased risk for heart disease and premature death (BMJ Sept 3, 2009;339).

Belly Fat is Risky Even if You Are Not Overweight

People who are not overweight and have a normal body mass index (BMI), but store most of their fat in their belly, are at increased risk for suffering a heart attack and dying prematurely (Annals of Internal Medicine, November 10, 2015). This study is among the largest and most rigorous studies ever on the harmful effects of belly fat. Researchers calculated the BMI and waist-to-hip ratios of 15,184 adults, ages 18 to 90, and followed them for 15 years.

Waist-to-hip ratio (WHR), but not BMI, was associated with higher overall risk for death. Men of normal weight and normal BMI but with belly obesity had an 87 percent higher risk of dying than men without belly obesity. Women with normal weight and belly obesity had a 48 percent higher death risk than women with similar BMIs but no belly obesity.

Another study shows that having extra belly fat and low levels of fat everywhere else markedly increases risk for arteriosclerosis (plaques in your arteries) and premature death in diabetics (Cardiovascular Diabetology, 10/13/2015). This study shows that storing fat primarily in the belly is associated with a high degree of arteriosclerosis and death in diabetics, even if they did not have much fat underneath the skin in the rest of their bodies.

Having extra belly fat is also associated with high cholesterol, high blood pressure, high blood sugar, inflammation, arteriosclerosis, heart disease, strokes, kidney damage, dementia, impotence, peripheral nerve damage and so forth. These risks are not associated with storing extra fat in the buttocks or thighs.

Dramatic Lifestyle Changes Can Save Lives

You have no choice about where you store your fat; your genes dictate whether you are shaped like an apple (big belly) or a pear (big hips and thighs). You are in trouble if you:

can pinch more than three inches of fat under the skin at the front of your belly, even if you are thin everywhere else

have a high fasting blood sugar (>95)

have high blood sugar two hours after eating (>120)

have high triglycerides (>150)

have a high HBA1C (> 5.5), which shows that you have too much sugar stuck on your cells

have extra fat in your liver (shown on a sonogram)

have pre-diabetes (metabolic syndrome)

If you have any of these risk factors for diabetes, or if you are already diabetic, you should immediately work to lose weight until you are down to less than one inch of fat over your belly. I think that the most efficient way to lose weight is intermittent fasting. For my recommendations on preventing and treating diabetes, see Treatment of Insulin Resistance and other reports in the Diabetes section of DrMirkin.com.

Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.